Production and storage of high concentration free radicals in matrix form suitable for high energy propellant use



1 1 5 3 6 0mm m ABS C ZIUS QwwTfl RNe Ah ELS EL RES FDL 0 NR OP Oct. 11,1966 F. E. NULL ETAL PRODUCTION AND STORAGE OF HIGH CONCENTRATI INMATRIX FORM SUITABLE FOR HIGH ENERGY Original Filed Sept. 12, 1963 F45/v C7764 K95 BY J MZWW VENTORS 04 a L x0 1 2 5 t 9 Wm m 7AES Cs. ZIUS Dt 3 A T 8 R N 8 Ah ELS EL RES F Oct. 11, 1966 F. E. NULL ETAL PRODUCTIONAND STORAGE OF HIGH CONCENTRATION IN MATRIX FORM SUITABLE FOR HIGHENERGY PROP Original Filed Sept. 12, 1963 INVENTORS F179 5. 11/0 my ,1

1m fiTTOzPA/' BY 5 3/ Q Oct. 11, 1966 F. E. NULL ETAL 3,278,351

PRODUCTION AND STORAGE OF HIGH CONCENTRATION FREE RADICALS IN MATRIXFORM SUITABLE FOR HIGH ENERGY PROPELLANT USE Original Filed Sept. '12,1963 5 h tsh t 5 #2 j) l4k Fig-E1 INVENTORS A4 9 5. #04 cme; A: as ewe 9rra ,eX/es/s Oct. 11, 1966 F. E. NULL ETAL 3,278,351

PRODUCTION AND STORAGE OF HIGH CONCENTRATION FREE RADICALS ELLANT USE INMATRIX FORM SUITABLE FOR HIGH ENERGY PROP Original Filed Sept. 12 1963 5Sheets-Sheet 3,278,351 REE RADICALS ELLANT USE Get. 11, 1966 F. E. NULLETAL PRODUCTION AND STORAGE OF HIGH CONCENTRATION F IN MATRIX FORMSUITABLE FOR HIGH ENERGY PROP Original Filed Sept. 12, 1963 5Sheets-Sheet. 5

J 5 k w mwa a W NW5 E a M .m a Q7 ZMQ FF W0 6 W m 2 n 1 United StatesPatent PRODUCTION AND STORAGE OF HIGH CONCEN- TRATIQN FREE RADECALS INMATRIX FORM %%HTABLE FUR HIGH ENERGY PROPELLANT Fay E. Null, Shalimar,and Carl Kyselka, Fort Walton Beach, Fla., assignors to the UnitedStates of America as represented by the Secretary of the Air ForceOriginal application Sept. 12, 1963, Ser. No. 308,605, now Patent No.3,242,683. Divided and this application Apr. 20, 1965, Ser. No. 449,654

7 Claims. (Cl. 149-15) This application is a division of applicationSerial No. 308,605 filed September 12, 1963, now Patent No. 3,242,683.

The invention described herein may be manufactured and used by and forthe Government for governmental purposes without the palyment to eitherof us of any royalties thereon.

This invention concerns an apparatus and a method for the production andthe storage of high concentration free radicals, representedillustratively by solid state atomic hydrogen laminated with molecularhydrogen for use as a propellant in projecting satellites into orbit, asa high explosive, and the like.

The detonation velocity and the brisance of the shattering effect ofhigh explosives determine the functional values of the explosives.

The objects of the present invention are to provide an apparatus, aprocess and a technique for laminating an atomic with a molecularelement, using hydrogen as the illustrative element, in the productionand in the storage of high concentrations of free radicals.

Other objects are to provide a high explosive of unusual power, animproved satellite propellant, and the like.

In the accompanying drawings:

FIG. 1 is a configuration representing a monolayer of molecularhydrogen;

FIG. 2 is a configuration representing the monolayer of molecularhydrogen molecules in FIG. 1 with hydrogen atoms adhering in randompositions at which the hydrogen atoms hit the monolayer of hydrogenmolecules;

FIG. 3 is a configuration of the monolayer of hydrogen molecules in FIG.1 with hydrogen atoms applied to the potential wells between thehydrogen molecules;

FIG. 4 is a sectional view, partly diagrammatic, of an apparatus thatembodies the present invention and for making the product that is ofinterest herein;

FIG. 5 is a fragmentary view, partly in section, taken about along theline 5-5 of FIG. 4.

FIG, 6 is a fragmentary view partly in section, and partly diagrammatic,of a first modification of an apparatus that embodies the presentinvention, for making the product that is described herein;

FIG. 7 is an axial section view of a single stage precooler, secondmodification of the apparatus for making the desired product;

FIG. 8 is a fragmentary axial sectional view of the sequential atomichydrogen and molecular hydrogen pulse making part of the apparatus inFIG. 7, displaced a onefourth turn on its axis;

FIG. 9 is a sectional view taken along the line 99 of FIG. 7;

FIG. 10 is an elevational view, partly in section, taken along the line10-10 of FIG. 7;

FIG. 11 is an elevational view of the film scraping knife in FIGS. 6, 7and 12;

FIG. 12 is a fragmentary axial sectional view of a third modification ofthe apparatus that embodies a multiple stage precooler ahead of thedeposition plate;

Patented Oct. 11, 1966 FIG. 13 is a plan view from above of acylindrical cooler; t

FIG. 14 is a sectional view taken along the line 1414 of FIG. 13,rotated one quadrant; and

FIG. 15 is a front elevational view of the cylindrical cooler in FIG.13.

The absolute, thermodynamic, or the Kelvin scale of temperatures, isbased on the average kinetic energy per molecule of a perfect gas. Thecomplete absence of heat and motion is the zero temperature of theKelvin scale and is 273.16 C. below the 0 C. of frozen water.

Helium melts at 10 K. and boils at 4.2 K. Hydrogen melts at 14.02 K. andboils at 20.4 K. Oxygen melts at 54.8 F. and boils at 902 K. Nitrogenmelts at 63 K. and boils at 77 K.

This invention discloses an apparatus and a method for depositing on asurface, a solid state monolayer of molecular hydrogen and then a solidstate monolayer of atomic hydrogen in the potential wells of themolecular hydrogen, and scraping the molecular-atomic lamination ofhydrogen as a solid matrix product, olf of the deposi tion surface, forits use as a propellant of satellites, as an explosive of highdetonation velocity and brisance or shattering effect, and the like.

The hydrogen free radical in a medium concentration, offers a uniqueopportunity to obtain research insight into the role of the free radicalin making determinations of the detonation velocity and the brisance ofexplosives. The hydrogen free radical has one of the requirements of aneffective explosive or propellant and that is a reaction with theliberation of a large quantity of energy. The energy liberated in thereaction H|-H H is 51,500 calories per gram as compared with the energyliberated in the reaction H /2O H O of 3,180 calories per gram.

The brisance of an explosive may be independent of the magnitude of theenergy liberated, depending in a complex manner upon the chain reactionsthat are involved. A single link of the chain reaction may act as abottleneck to delay the speed of formation of the end product, and thusto decrease the power expended, and to degrade the explosiveperformance.

According to the precursor theory advanced by Mr. Fred Howard, Jr., ofthe Eglin Air Force Base, Florida, powerful explosives have a precursorwave of fast particles that precede the detonation wave, and one of itseffects is to dissociate some of the molecules of the explosive to formfree radicals. This precursor formation of free radicals may short outsome of the bottlenecks in the chain reaction permitting direct chemicalreactions, and the high velocity detonation wave that characterizes thehigh explosive.

The direct recombination of free radicals would not be prevented by acomplicated chain reaction, and with simi lar concentration and densityto that of a conventional high explosive, should produce a higherbrisance. It is well-known that a high detonation velocity depends upona high density, and that concentrations of the hydrogenfree radical ofaround 1% do not show any evidence of an explosion. It is, therefore,necessary to produce the hydrogen-free radical in a relatively highconcentration.

According to the teachings of John M. Flournoy of the Aero Jet GeneralCorporation, low concentrations of the free-hydrogen radical are readilyproduced either by the trapping of gaseous radicals or by the irraditionof materials at low temperatures.

The basic problem in producing concentrations of the hydrogen-freeradical, exceeding 1 mole percent in a solid matrix, involves heatdissipation. For example, when a free radical from an electricaldischarge is trapped on a plate at 4.2 K. which, as previously stated,is the boiling point of helium, the heat of sublimation and the kineticenergy of the free radical must be dissipated on a collecting surface.As the hydrogen deposited in the solid state is a poor heat conductorwith a low specific heat, the solid surface rises in temperature untilthe rate of recombination of atomic hydrogen into molecular hydrogen isapproximately equal to that of its deposition on the solid surface.

John M. Flournoy suggests methods for overcoming this difiiculty, suchas, the exceedingly slow deposition from the gas phase or the precoolingof the gas atoms and molecules before being trapped. It appears thatprecooling of the gas atoms and molecules should be practiced in anyevent, but it does not get rid of the heat of sublimation.

An extremely slow rate of deposition of hydrogen atoms and of hydrogenmolecules properly permits a higher concentration of atomic hydrogen,but in practice it would require the deposition in a vacuum of 10- or 1Omillimeters of mercury. The collection of an appreciable amount ofhydrogen-free radicals would be a long operation unless techniques weredeveloped to use very large condensing surfaces.

At the temperature of liquid helium, which boils at 42 K., collision ofgaseous hydrogen atoms on a solid surface of deposition, might not beentirely prevented so that some recombination would occur, the excessenergy of the combining pairs being given to the crystal lattice in theform of vibrational energy. Even a small percentage of recombinationwould greatly augment the heats of cooling and condensation, and a highconcentration of atomic hydrogen, even though it be at a low density,would give up entirely too much heat to be transmitted through a thick,solid layer and trapped atomic hydrogen would no longer be stabilized.

The practical solution to the above problem of heat dissipation, asdisclosed herein, is by the alternate deposition of monolayers of atomichydrogen and molecular hydrogen, with a mechanical scraping off of thecomposite layer before it is thick enough to impede the escape of heatto the metal wall maintained at the boiling point of natural heliumwhich is 4 K.

In FIG. 1 of the accompanying drawings is shown a monolayer of molecularhydrogen molecules 1. It is not known Whether the hydrogen atoms 2 willstick where they hit on the molecules 1 of hydrogen, as represented inFIG. 2 of the drawings, or whether they will migrate short distancesover the solid surface to positions of minimum potential, such as arerepresented in FIG. 3 of the drawings. At the boiling point of helium,4.2 K., it is also not known to what degree of separation atoms ofhydrogen will remain on the substrate without collision andrecombination into molecules, as is represented at 4 in FIG. 2 of thedrawings.

In the publication, Physics Today, vol. 11, pages 14- 16, published inFebruary 1958, Professor Davidson presents some evidence of thediffusion of free radicals for at least a few molecular diameters in aninert solid matrix which, it may be presumed, permits hydrogen atoms toseek out positions of minimum potential.

This general theorization is presented in FIGS. 1 to 3, inclusive, ofthe accompany drawings. In FIG. 3, free radical hydrogen atoms 2 arepresumed to migrate to positions of minimum potential at interspacialpositions 3 between the hydrogen molecules 1. The configuration in FIG.3 is taken to be symbolic of the actual lattice structure involved.Hydrogen atoms in bulk may be assumed to form a body-centered, cubiclattice structure.

Thin layers of hydrogen atoms are influenced by the structure of thesubstrate, so that successive monolayers of different substances may beassumed to be influenced most by two-dimensional geometry.

On the other hand, if the atomic hydrogen 2 sticks where it hits on themolecular hydrogen layer, as is illustrated in FIG. 2 of the drawings, arandom distribution results. In this latter situation, some of theatomic hydrogen may be assumed to hit closely enough together to collideand recombine, as is represented at 4 in FIG. 2. It is believed,however, that due to the small size of the hydrogen atom 2 as comparedwith the hydrogen molecule 1, collisions of this type would berelatively rare and the heat of recombination would be readily carriedoff through the thin structure of molecular and atomic monolayers ofhydrogen.

The arrangement in FIG. 3 would appear to be preferable, depending uponthe depth of the potential wells at the position 3, as compared with thevapor pressure of atomic hydrogen at 42 K., and the resultant resistanceto collision and to recombination. The configuration in FIG. 2 isfavored as it decreases the available surface migration time of atomichydrogen with a shorter time interval between the deposition of atomicand molecular layers.

An apparatus for obtaining a high concentration of atomic hydrogen isshown in FIGS. 4 and 5 of the accompanying drawings. The apparatus isused in accomplishing the deposition of alternate monolayers of atomicand molecular hydrogen on the surface of a rotating drum 5 that ismaintained at the 4.2 K. temperature of liquid helium. The hollow drum 5is mounted on the hollow shaft 6. The shaft 6 is journalled in suitablebearings 7 and is turned by the gear 8. The gear 8 is meshed with asmaller gear 9, driven by the shaft 10 supported in the bearing 11, bythe motor 12.

Atomic hydrogen passes through the channel 15 to the surface of thecylinder 5. Molecular hydrogen passes through the channel 16 to thesurface of the cylinder 5.

The combination of atomic hydrogen to form molecular hydrogen within thechannel 15 is minimized by a very small layer 17 of plasma sprayedsilicon dioxide which is poisoned in a suitable manner by a trace ofsolidified oxygen, solidified water, or the like. This practice is inconformity with the teachings of R. W. Wood of the Johns HopkinsUniversity expressed in his article entitled Atomic Hydrogen and theBalmer Series Spectrum in the Philosophical Magazine 6 SER vol. 44,published in 1922. K. E. Shuler and K. J. Laider in their article in theJournal of Chemical Physics, vol. 17, page 1356, published in 1949,state that at K., which is the boiling point of liquid oxygen, a coatingof ice reduced the recombination rate of hydrogen atoms by a factor of10 to 10 Both of the channel walls 15 and 16 are provided withexternally disposed cooling jackets 18 and 19, respectively, beneath orthrough which jacketed compartment liquid hydrogen flows at 20 K., atwhich temperature the molecular hydrogen does not condense out. Atomichydrogen has a higher vapor pressure than molecular hydrogen and alsodoes not condense out on the walls of the channel 15.

The drum 5 contains liquid helium which maintains its surfacetemperature at approximately 4 K. The liquid helium is fed into thehollow, steel drum 5 through apertures shown in the hollow fused quartzaxle or shaft 6 from a fill plug 20 at the end thereof, where the shaftis turned by the gear 8. The fused quartz axle 6 preferably isjournalled in Invar bearings.

The hollow drum 5 is enclosed within a desired plurality ofprogressively temperature lowering jackets, such illustratively as thejackets 21 to 24, inclusive, that are illustrated in FIGS. 4 and 5. Thespace between the inner jacket 21 and the jacket 22 is filled withcontinuously circulating liquid helium that is maintained at thetemperature of about 1 to 4 K. The space between the jacket 22 and thejacket 23 contains continuously circulating liquid hydrogen maintainedat the temperature of about from 1420 K. Liquid oxygen is circulatedbetween the jackets 23 and 24 that are maintained at the temperaturerange of from 5590 K. The jacket walls are good thermal insulators, eachwall having a composite structure, as vacuum between layers of glass, orglass wool separated by aluminum foil. Apparatus support is indicated bythe partition 26. The whole assembly is enclosed within a vacuum chamberWall 25 within which is maintained a vacuum of about l to l0 of mercury.

Within the jacket 21 that encloses the drum 5, and attached to theinterior of the jacket 21, is a cylinder 31 that encloses a piston 32.The piston 32 is connected through a thrust member passing through apiston cap 33, with a knife blade 34. The knife blade 34 edge is of thesame length as the axial length of the drum 5 and releasably makesscraping engagement with the surface of the drum for stripping the filmtherefrom.

The piston 32 is loaded downwardly by the coil spring 35. The piston 32is actuated by helium gas or liquid pressure supplied from the pipe 36under the control of the valve 37. The helium gas is supplied to thevalve 3'7 from the supply pipe 38 and is released through the dischargepipe 39. The helium gas applies pressure against the piston 32 tocompress the coil spring 35 and to apply the edge of the knife blade 34against the surface of the rotating cylinder 5. The application of theedge of the blade 34 to the full axial length of the surface of thecylinder 5 removes the laminations of atomic hydrogen and molecularhydrogen in their solid states therefrom as product, of laminated mosaicstructure.

The composite layer product 40 that is removed by the edge of the blade34 from the surface of the cylinder 5 accumulates within the compartmentthat is provided by the jacket 21 from which it is removed by theoperation of the door 27 that slides laterally under the guides 28 and28'. The blade 34 is disengaged from the surface of the drum 5 byoperating the valve 37 to exhaust the precooled helium gas through theexhaust pipe 39. The helium gas or helium liquid is maintained at a lowtemperature to minimize heat flow toward the drum 5.

The pressure of the atomic hydrogen within the channel 15 for thedeposition of a monolayer on the drum 5 illustratively is estimated tobe 5.8x millimeters of mercury. A composite layer that is a tenth of amillimeter thick is estimated to consist of 425,000 monolayers. Apreferred velocity of the drum 5, traveling at 3,000 feet per second andwith a slit 10 centimeters wide, with an estimated time of transit ofl.09 l0" seconds, permits the accumulation of the composite film product40 of a thickness of a tenth of a millimeter in 46.4 seconds, with anannual productiton for each apparatus of about 20 tons of explosive orpropellant.

Since the peripheral surface of the cylindrical drum 5 is cooled byliquid helium that is pressed against the inside surface of the drum 5by centrifugal force, it is estimated that the tensile strength of thesteel drum 5 should be in the order of 300,000 lbs. per square inch witha preferable surface velocity of about 1,330 feet per second. Theperipheral strength of the steel may be augmented by being wrapped withfine wire without impairing the conduction of the heating condensationthrough the drum surface to the liquid helium disposed inwardly of thedrum 5. It is estimated that the wire-wrapped drum would Withstand twicethe tensile strength of an unwrapped drum.

It is preferred that the shaft 6 be made of fused quartz to minimize theconduction of heat thereby. The shaft 6 bearings illustratively are madeof Invar metal that is coated with powdered graphite. The assemblythroughout is constructed of material that minimizes heat flow.

In FIGS. 6 to 12, inclusive, of the drawings, are shown modifications ofthe apparatus that is shown in FIGS. 4 and 5. The modifications comprisebroadly a rigidly mounted, flat, film matrix product deposition platethat replaces the cylindrical drum 5 in FIGS. 4 and 5; means forproducing sequential pulsations of atomic hydrogen and of molecularhydrogen gases conducted by a single channel instead of the two channelsin FIG. 4; means for delivering the gaseous pulsations for theirsolidification and deposition as sequential laminations as a matrixprodnot on the surface of the deposition plate; and supplementalapparatus. The single channel conducted pulsations of atomic hydrogenand of molecular hydrogen applied to the rotatable drum 5 applies asolidified matrix thereto, as a laminated mosaic.

In FIG. 6 of the accompanying drawings, is shown a first modificationwherein alternate pulsations or waves of atomic hydrogen and ofmolecular hydrogen from a wall-cooled expansion nozzle 46 aresuccessively applied to the surface of a rectangular, fiat, stationarydeposition plate 45. The stationary deposition plate 45 is maintained atthe temperature 4 K. by liquid helium that is positioned between thejackets 47 and 48 that are mounted immediately back of the plate. Thepair of jackets 48 and 49 define a compartment Within which liquidhydrogen at about 14 K. is continuously circulated. Additional jacketsfor providing stepped temperature control, as in FIG. 4, are availableas desired.

The interior surface of the expansion nozzle 46 is coated with a verythin layer of silicon dioxide that has been sprayed thereon, to which isadded water vapor, phosphoric acid or oxygen that serves to prevent therecombination of atomic hydrogen into molecular hydrogen. A jacket 52 isdisposed outside the expansion nozzle 46 to provide a thin compartmentthrough which is circulated liquid hydrogen at the temperature of 14 K.The jacket 52 may be augmented by additional cooling jackets as desired.

Solidified alternated laminations of atomic hydrogen and of molecularhydrogen are removed from the surface of the fiat, square or rectangulardeposition stationary plate 45 by a suitable means, such as by the knifeblade 55. The knife blade 55 is of the length corresponding to the widthof the surface of the stationary, flat deposition plate 45, as shownprimed in FIG. 11 and doubleprimed in FIG. 12.

The knife blade 55 extends laterally of, is normal to, and is actuatedby a piston rod 56. The piston rod 56 terminates downwardly in a piston57 that reciprocates within a cylinder 58. The piston 57 isspring-loaded downwardly by operation of the coil spring 59. The edge ofthe knife blade 55 serves to remove sheets of solidified compositelayers of atomic hydrogen and of molecular hydrogen product 40 from thesurface of the deposition stationary plate 45 by the operation of thevalve 50.

When the composite layer on the deposition plate 45 reaches the desiredthickness, the knife scraper 55 is caused to move upwardly of thedeposition plate by the admission of cooled gaseous or liquid heliumthrough the valve supplied by the inlet pipe 53. The liquid helium isapplied to the lower surface of the piston 57 within the cylinder 58 andcompresses the spring 59 until the knife blade reaches the top of thedeposition plate 45, during which travel the sheet of the atomichydrogen and molecular hydrogen laminate matrix product 40' is shearedfrom the deposition surface of the plate 45 and accumulates within thecontainer below the plate 45. The removal of the laminate from inside ofthe device is accomplished through a suitable door 41 that is hinged atone edge and that is released by the operation of the catch 42.

Upon the knife blade 55 reaching the upper extremity of its travel, thespring 59 expands against the upper side of the piston 57 returning itto the lower end of the cylinder 58 in response to the adjustment of thevalve 50, causing the liquid helium to drain away through the outletpipe 54. This process is repeated at sufficient intervals determined bythe thickness of the deposition of the lamination of atomic hydrogen ormolecular hydrogen accumulated on the deposition plate 45.

In the device that is shown in FIGS. 7, 8 and 9 of the drawings, gaseoushydrogen is admitted from the hydrogen supply pipe 60 at a flow ratethat is adjusted to its rate of conversion into its end product 40". Thegaseous hydrogen passes through a hydrogen metering valve and thenbetween a pair of electrodes 61 and 61' that are alternately energizedand de-energized. Each time a spark passes between the adjacent tips ofthe electrodes 61 and 61' an estimated 94.7% by weight 'of the molecularhydrogen between the electrode tips is converted into atomic hydrogenwith a temperature increase of about 5,000 K. As a result, alternatepulses of atomic hydrogen and molecular hydrogen pass to the right ofthe spark chamber 62 through the throat 63 and are conducted along theexpansion nozzle 46 toward a preferred precooling unit at diminishingrates of flow and temperature until they sequentially arrive at thedeposition plate 45 with a minimum velocity. Atomic hydrogen forcommercial use is obtained by directing a jet of hydrogen gas at rightangles to a hydrogen arc. The molecular hydrogen metering valve providesapparatus for imparting alternating pulsations of atomic andmolecular'hydrogen that are fed into the spark chamber 62.

The spark chamber 62 is provided with a water jacket 71 through whichcold water flows between the connections 65 and 66. The wall of theexpansion nozzle 46 is provided with a desired sequence of coolantcompartments for circulation through pairs of connections 67 and 68, 69and 70, and the like, such as water, liquid oxygen, liquid nitrogen,liquid hydrogen, or the like.

The expansion nozzle 46 is of adequate dimension axially to permit thedesired temperature reduction from 5,000" K. at the arc between theelectrodes 61 and 61 to the arrival of the gas at the deposition plate45 in FIG. 6 or 45 in FIG. 7, or at one of the precoolers in FIG. 7 orFIG. 11. However, the velocity of the gas is then very high, and theprecoolers absorb the corresponding excess kinetic energy before impacton the deposition plate.

The expansion nozzle 46 is designed to deposit on the plate 45 theamount of gas in the pulse in a uniform nionolayer, the gas at its mouthbeing in the transition range between slip flow and free molecular flow.The hydrogen gas expansion is adequate for providing a widely dispersed,low density, fairly uniform flow of gas. The density of the pulse jettrails off as it approaches the plate on which it is to be deposited,due to the method of the pulse production and through the use of theequipment shown in FIGS. 6 to 12, inclusive, of the drawings. At thedeposition surface of the plate 45, the pulse density is substantiallyuniform in the direction that is parallel to the surface of thedeposition plate.

The metering valve for supplying hydrogen to the spark chamber 62 thatis shown in FIGS. 7, 8 and 9 of the accompanying drawings, is designedfor high-speed operation. The hydrogen metering valve comprises arotating disc 86 that is positioned between a pair of non-rotatingplates 87 and 88 using powdered graphite therebetween as lubricant. Therotating disc 86 has a fill port 83 that is adjacent to its peripheraledge. The rotating disc 86 is mounted upon the end of a shaft 84 towhich the disc is secured in the usual manner between the bolt head 80and the screw nut 82. The stationary plate 87 is adapted for beingslidable axially along the end of the hydrogen supply tube 60 under theurging of suitable means such as the spring-loaded piston 90 in thecylinder 91. In a similar manner, the other stationary plate 88 isslidable axially along the extension 94 at the left-hand end of thespark chamber 62. Both plates 87 and 88 are spring-pressed axiallyagainst the rotating plate or disc 86. The axial pressure is applied bya spring 92 that maintains a thrust bar 93 in engagement with thestationary plate 87 as by seating in an aperture therein as shown. Asimilar arrangement applies axial pressure to the plate 88 as shown inFIG. 8 with the parts primed. In both instances, the cylinders 91 and 91are secured in position. As a result, the rotating plate 86 iscontinuously compressed axially between the two plates 87 and 88 withthe assembly serving as a hydrogen conducting and pulsing valve.

The overall apparatus is designed to accomplish a uniformly taperingexpansion of the gas with a continuous separation front between themolecular and the atomic hydrogen gas pulsations.

In the apparatus that is illustrated in FIGS. 7, 8 and 9 of theaccompanying drawings, the entrance slit 64 into the spark chamber 62 isdimensioned such that the fill port 83 in the rotating disc 86, that ispositioned between the stationary plates 87 and 88, is about ten timeslonger than the entrance slit 64, such that the time spent during thepassage of the front or lead edge of the fill port 83 in passing acrossthe hydrogen entrance slit 64 is small as compared with the time thefill port 83 is open and, such that the time for the rear edge of thefill port 83 to cross the entrance slit is quite short. For most of theopen time of the fill port 83, the flow of gas is uniform.

The single stage precooler that is shown in FIG. 7 of the accompanyingdrawings is attached to the discharge end of the expansion nozzle 46' toreceive the alternated atomic hydrogen and molecular hydrogen pulsationstherefrom prior to their arrival at the deposition plate 45'.

The expansion nozzle 46 in FIG. 7 is of frusto-conical shape. Theexpansion nozzle may terminate at its discharge right-hand end in acircular section, in a square section, or in a rectangular section, aspreferred, within the concept of this invention.

The precooler at the discharge end of the expansion nozzle has a sectionthat conforms with the section of the expansion nozzle to which it issecured by bolts, welding, or the like, not shown. The deposition platethat follows the precooler, may, if preferred, be of a contour thatconforms with the section of the discharge end of the precooler.

The single stage precooler of circular cross-section is shown in FIGS.13, 14 and 15 of the drawings. The precooler is shown as a cylinder inplan view from above in FIG. 13, and in cross-section in FIG. 14. Anelevational view of the intake end of the cylindrical precooler is shownin FIG. 15.

The cylindrical precooler comprises a desired plurality of circularlyextending, thin and continuously hollow vanes 110, etc. The vanes openinto and are supported by a diametrically, vertically extending header111 that in section may be circular, oval, or square, as preferred. Theheader 111 extends between a liquid hydrogen supply pipe 112 and adischarge pipe 113.

The axally opposite ends of the hollow vanes 110, 110, etc., terminatein small angle apices that minimize the introduction of disturbance inthe flow of pulsed atomic and molecular hydrogen gas as it passesthrough the vanes, as indicated in FIG. 13, by the central vane conicaltip 114. The opposite axial ends of the circular vanes 110, 110', etc.,are supported by a gas permeable apertured plate or spiders 115 or 116,by being welded to the spider spokes 117, 117', or the like. Theradially inner rim 118 of the spider 115 is welded to the base of thecentral vane conical tip 114. The radially outer rims of the spiders 115and 116 are welded respectively to the opposite ends of the outermostvane 110. g

The single stage precooler that is shown in FIG. 7 of the drawings, isof a square or a rectangular section that matches or conforms with thesquare or the rectangular right-hand discharge end of the expansionnozzle 46.

The single stage precooler that is shown in FIG. 7 comprises a desiredplurality of straight, horizontally extending hollow vane 77, 77, etc.The lateral ends of the vanes are supported by, attached to, and openinto vertically extending hollow header member parts of the closed ringheader 76, 76. Both the closed ring header 76, 76', and the vanes arenarrow. The vanes terminate at their axially front and rear edges insmall angles to minimize disturbance in the flow of hydrogen gas aroundthe vanes. Liquid hydrogen at 14 K. is continuously circulated from itsinput pipe 96 through a compartment 9 between the panels 73 and 75 intothe header 76 to its output pipe 78 that opens from the header 76'.

The deposition plate 45 overlies the discharge end of the precooler. Thedeposition plate 45' is backed by a liquid helium at 4 K. containingcompartment between the jackets 72 and 73 fed from the pipe 74. Theliquid helium compartment back of the deposition plate 45 is protectedfrom heat absorption by the liquid hydrogen compartment between thejackets 73 and 75 and by additional supplementary compartments, wheredesired.

The dotted lines before the intake ends of the vanes 77, 77, etc.,represent shocks 79 that are in front of the lead ends of the hollowvanes 77, 77, etc., of the pre cooler. The lead edges of the precoolervanes 77, 77, etc., are designed to convert much of the kinetic energyof the hydrogen flow into thermal energy for rapid heat flow to theprecooler.

The individual shocks 7-9 blend into a normal shock 79' which tends toaverage out in the subsonic flow downstream of the normal shock. Thecooling vanes 77, 77, etc., illustratively are about three inches apart.The collisions of atoms and molecules at the entrance end of the hollowvanes 77, 77, etc., cause the atoms and molecules to bounce back or tobe re-emitted at velocities approaching the thermal equilibrium valuefor the surface. This results in a drastic reduction in the velocity ofthe reemitted atoms and thereby produces a corresponding increase in thedensity and a decrease in the mean free path of the more forward flowingatoms and molecules. The re-emitted or the recoil atoms from one vane gobut a short distance before hitting another vane which, in turn,re-emits them toward the first vane, with the results that the atoms andthe molecules are given a marked increase in density, an increase inpressure, and an increase in temperature, that are characteristic ofcrossing a shock front. The thickness of the shock front is not crucialto the production of free radicals. The axial length of the hollow vanes77, 77', etc., is adjusted to obtain the degree of precooling that isdesired.

The alternate pulses of atomic hydrogen and molecular hydrogen arecaused to adhere to the surface of the stationary deposition plate 45'as sequential laminations of atomic hydrogen and molecular hydrogen thatpreviously have adhered thereto. The overall dimensions of the precoolerare such as to maintain a supply of atomic and molecular hydrogen atabout 20 K. or below. The exposed surface of the precooler is adequateto cool down the pulsed supply of atomic and molecular hydrogen and toremove the stagnation heat that is released in the slowing down of thegas by skin friction.

The channels between the precooler hollow vanes 77, 77', etc., arefilled with gas of very low density. The sum of the kinetic and of thethermal energy of the gas about equals the thermal energy of thestationary gas in equilibrium with the wall at 20 K. Thus, the atomichydrogen arrives at the deposition plate 45 with about the equivalentthermal energy of a gas at 20 K.

The rate of build-up of the composite layer on the stationary depositionplate 45' depends on the number of pulses of atomic hydrogen and ofmolecular hydrogen that arrive at the plate and, hence, it is found tobe necessary to fill the spark chamber 62 with hydrogen at a rate thatprevents mixing of the admitted hydrogen gas with the tail-off pressureof the previous pulse of atomic hydrogen.

The product 40" in FIG. 7 is removed as before by the edge of the knifeblade 55' that functions in the same manner as the correspondingassembly in FIG. 6.

In FIG. 12 of the accompanying drawings is shown a modification of thepresent invention that embodies a multiple-stage precooler that ispositioned ahead of the rectangular stationary deposition plate withevacuated separators between the stages.

In FIG. 12 the expansion nozzle 46 is lined as before with a layer 511"that is poisoned to minimize the recombination of atomic hydrogen intomolecular hydrogen. The nozzle wall, maintained at a desired lowtemperature by a coolant which is circulated between the wall of theexpansion nozzle and one or more jackets 52, of which the connection 68'is representative.

The multiple-stage precooler broadly comprises a plurality ofrepetitions of the precooler of FIG. 7. The stages are mutuallyinsulated thermally by shallow dividers that are evacuated to 10* or l0millimeters of mercury. The precooler first stage is representative ofall the stages shown and comprises a vertical header or manifold thatreceives its cooling liquid from the supply pipe 101 for circulationthrough the manifold and through the circularly or transverselyextending hollow vanes with cross-sections 102, 102', etc., that openlaterally into and are attached to and supported by the upright sides ofthe manifold. The exhaust manifold (not shown) corresponds to 76' inFIG. 7. That fraction of the coolant that undergoes its transition fromits liquid to its vapor phase is conducted by the discharge pipe 103 toa compressor, a condenser, and a pump that are not shown, and thatreturn the coolant in its liquid state through the input pipe 101. Theshallow evacuated dividers 104, 104', etc., are exhausted by a pipe 105to the vacuum. Corresponding parts for the sequential stages bearcorresponding numerals primed successively.

The stationary deposition plate 45" has a surface on which thesuccessive pulses of atomic hydrogen and molecular hydrogen, that passthrough the precooler, solidify in successive laminations. Thetemperature of the deposition plate is maintained at 4 K. by liquidhelium that is continuously circulated between the jackets 72 and 73'from connections such as the connection 74'. The liquid helium containerback of the deposition plate 45' is backed up by a desired succession ofstepped coolant containing compartments, such illustratively, asmultiples of the liquid hydrogen compartment between the jackets 73' and75 through which liquid hydrogen is circulated through the connection96'.

The laminated solidified layers of atomic hydrogen and molecularhydrogen that are deposited on the surface of the deposition plate 45"are removed by the edge of the knife blade 56" that extends for the fullwidth of the deposition surface and that is operated by gaseous orliquid helium as described for FIG. 6. The laminated matrix product 40is entrapped within a compartment such as that described for FIGS. 4 and6, and is removed as previously described for those particular pieces ofapparatus.

It is to be understood that the steps of the method, the laminatedatomic hydrogen and molecular hydrogen products and the apparatus thatare disclosed herein, have been submitted as being illustrativereductions to practice of the present invention and that correspondingmodifications may be made therein for accomplishing comparable resultswithout departing from the spirit and scope of the present inventiondefined by the claims that appear herein.

We claim:

1. The process of making and storing a plurality of high-concentrationfree radicals by the steps of chilling a deposition surface at atemperature that is below the temperature at which the free radicalsassume their solid states, and sequentially impacting the plurality offree radicals in their vapor state against the deposition plate wherethe impacted free radicals form a solid state laminated matrix product.

2. The process of making a solid state matrix of molecular hydrogen andatomic hydrogen by maintaining a rotatable cylinder surface temperatureat about 4 K., conducting to the rotatable cylinder surface molecularhydrogen vapor for its solidification on the surface of the cylinder,and conducting to the rotatable cylinder surface atomic hydrogen vaporfor its solidification on the solidified molecular hydrogen as the solidstate matrix product.

-3. The solid state matrix comprising substantially a monolayer ofmolecular hydrogen, and substantially a monolayer of atomic hydrogenbonded to the monolayer of molecular hydrogen.

4. The solid state matrix product that comprises in its space lattice aplurality of laminations of monolayers of molecular hydrogen havingpotential wells, and an atom of hydrogen substantially at each of thepotential Wells of the molecular hydrogen in the product space lattice.

5. The process of producing and storing a plurality ofhigh-concentration free radicals by the steps of metering a gas byrotating a disc that is apertured adjacent its periphery by a fill port,compressing the disc axially of the assembly between a pair ofstationary plates and causing the gas passing through the disc fill portto enter a spark chamber slit that is dimensioned one-tenth of the discfill port, passing a spark through alternate pulses of the gas meteredby the disc fill port and passing the spark chamber slit for atomizingsubstantially 95% by weight of the gas in atomized pulses of the gasalternated with molecular pulses of the gas, passing the alternatepulses of the gas axially of an expansion nozzle, and sequentiallyapplying the alternate pulses of the gas as free radicals in their vaporstate to a deposition surface that is maintained at a temperature thatis below the solidification of the free radicals for the solidificationof the gas pulsations as a solid state laminated matrix product.

6. The process of making a laminated matrix consistmultiplicity ofmolecules of the same element, by channeling a vapor flow of atoms ofsaid element toward a deposition surface that is at a temperature belowthe freezing point of said element, and channeling a vapor flow ofmolecules of said element toward the said deposition surface, andalternating the impaction on the said deposition surface of the vaporflow of atoms with the vapor flow of molecules in building a solidmatrix on the deposition surface, and removing the matrix from thedeposition surface.

' 7. The process defined in claim 6 wherein the element is hydrogen withits free radical hydrogen atoms migrating to interspatial positions ofminimum potential between hydrogen molecules of the solid matrix.

References Cited by the Examiner BENJAMIN R. PADGETT, Acting PrimaryExaminer.

3. THE SOLID STATE MATRIX COMPRISING SUBSTANTIALLY A MONOLAYER OFMOLECULAR HYDROGEN AND SUBSTANTIALLY A MONOLAYER OF ATOMIC HYDROGENBONDED TO THE MONOLAYER OF MOLECULAR HYDROGEN.
 5. THE PROCESS OFPRODUCING AND STORING A PLURALITY OF HIGH-CONCENTRATION FREE RADICALS BYTHE STEPS OF METERING A GAS BY ROTATING A DISC THAT IS APERTUREDADJACENT ITS PERIPHERY BY A FILL PORT, COMPRESSING THE DISC AXIALLY OFTHE ASSEMBLY BETWEEN A PAIR OF STATIONARY PLATES AND CAUSING THE GASPASSING THROUGH THE DISC FILL PORT TO ENTER A SPARK CHAMBER SLIT THAT ISDIMENSIONED ONE-TENTH OF THE DISC FILL PORT, PASSING A SPARK THROUGHALTERNATE PULSES OF THE GAS METERED BY THE DISCS FILL PORT AND PASSINGTHE SPARK CHAM-